﻿// Copyright 2007-2015 Chris Patterson, Dru Sellers, Travis Smith, et. al.
//  
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the 
// License at 
// 
//     http://www.apache.org/licenses/LICENSE-2.0 
// 
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 
// CONDITIONS OF ANY KIND, either express or implied. See the License for the 
// specific language governing permissions and limitations under the License.
namespace MassTransit.Monitoring.Performance
{
    using System;
    using System.Collections.Concurrent;


    public class ConsumerPerformanceCounterCache
    {
        readonly ConcurrentDictionary<string, Lazy<ConsumerPerformanceCounter>> _types;

        ConsumerPerformanceCounterCache()
        {
            _types = new ConcurrentDictionary<string, Lazy<ConsumerPerformanceCounter>>();
        }

        public static IConsumerPerformanceCounter GetCounter(ICounterFactory factory, string consumerType)
        {
            return Cached.Counter.Value._types
                .GetOrAdd(consumerType, x => new Lazy<ConsumerPerformanceCounter>(() => new ConsumerPerformanceCounter(factory, x)))
                .Value;
        }


        static class Cached
        {

            public static readonly Lazy<ConsumerPerformanceCounterCache> Counter =
                new Lazy<ConsumerPerformanceCounterCache>(() => new ConsumerPerformanceCounterCache());
        }
    }
}
